The work under progress involves the recording of the electrical signals of the retina (electroretinogram--ERG) and the cortex (visually evoked potentials--VEP) as a means of studying the human visual system in the normal and diseased state. The research program includes: (1) the use of a pattern stimulus of constant mean luminance to record the ERG and VEP in patients with retinal cone dysfunction; (2) the investigation of the electrophysiological correlates of amblyopia using the ERG and VEP in adults and the VEP in children; (3) recording of the pattern VEP in normal infants from 2 to 6 months of age as a means of measuring their visual acuity and contrast sensitivity; (4) study of various types of neuro-ophthalmic disorders using the VEP.